Remove usage of ScopedAsyncTaskScheduler from SequencedModelWorkerTest.

ScopedAsyncTaskScheduler is deprecated.

Bug: 708584
Change-Id: If36e43e68fe63bee75f2b34f13f98acaa8571f1c
Reviewed-on: https://chromium-review.googlesource.com/591988
Reviewed-by: Stanislav Chiknavaryan <stanisc@chromium.org>
Commit-Queue: Francois Doray <fdoray@chromium.org>
Cr-Commit-Position: refs/heads/master@{#490775}
1 file changed